BatchProcessor exception handler is not triggering

Expected behaviour:

When registering an exceptionHandler in BatchOptions, it should be invoked when data cannot be written.

Actual behaviour:
The handler isn't invoked, not even when attempting to write to a database that cannot even be connected to (because it doesn't exist). Log calls invoked by it are not showing up in the log, and debugging breakpoints set in the handler are never triggered.

This is how I register the handler (Kotlin syntax, but you should easily get the idea):
```
InfluxDBFactory.connect(props.uri, props.user, props.password).apply {
setDatabase(props.name)
enableBatch(BatchOptions.DEFAULTS.exceptionHandler { point, e ->
log.error("Error during write", e)
})
}
```

I can run this code against a bogus uri, and the handler doesn't trigger. Am I doing something completely wrong here?

Start with BatchOptions.exceptionHandler, enableBatch, and the BatchProcessor path used after InfluxDBFactory.connect. Reproduce the report with a bogus URI and trace whether write failures reach the registered handler. Done means the handler is invoked and its log output is observable for an unwritable database.

Scritto dal modello di indicizzazione a partire dal testo della issue.